Why Does an Object Thrown Vertically Decrease in Speed Until its Velocity is 0?

[MattKiren]

I'm currently in the process of writing a practical report and am wondering whether any can explain to me why an object will decrease in speed until its velocity is 0

Preferably in an if... then... because... statement.

 

[davenn]

Hi there
welcome to PF

wondering whether any can explain to me why an object will decrease in speed until its velocity is 0

why do you think it does ?
what forces do you think are acting on the object ?Dave